1. Field of the Invention
The present invention relates to an electronic circuit for television receivers for amplification and transformation of very high frequency and of ultra high frequency signals into an intermediate-frequency signal with a high frequency input stage provided for each frequency region, a mixing stage, a bandpass filter tuned to the intermediate frequency and an intermediate frequency amplifier.
2. Brief Description of the Background of the Invention Including Prior Art
Such circuits for signal processing in television receivers are generally known. The signals decoupled via the intermediate frequency bandpass filters are directly fed to the intermediate-frequency amplifier. However, this is associated with several disadvantages, which are expressed in that during production and after the electrical connection of the tuner to the intermediate-frequency amplifier both have to be retuned to the intermediate-frequency because of the different output or, respectively, input frequencies. Also a repair requires a new balancing and tuning, but this is frequently not possible in view of a lack of the necessary testing equipment and this becomes very expensive. If the tuning and balancing is not performed, then the bad matching between tuner and intermediate-frequency amplifier causes more or less reflections of the signal.